Stage 1: Stage 1 of the study will investigate dose escalation of a single intratumoral injection over the following dose levels: 1 x 10^5 TCID50, 3 x 10^5 TCID50, 1 x 10^6 TCID50, and 1 x 10^7 TCID50. In Stage 1, it is planned that 3 patients will be enrolled per single dose cohort. Within each single dose cohort, accrual will temporarily be suspended after the first patient is entered and the patient will be followed for safety and for viral distribution and elimination. The patients in Stage 1 must be seropositive for HSV-1.